EP1196696B1 - Rotor with a split rotor blade - Google Patents

Abstract

A rotor through which a fluid flows in a main direction of flow, provided with at least one rotor blade, the rotor blade being arranged to rotate about a rotor axis. The rotor blade extends away from the axis of rotation into the field. To reduce the trailed tip vortex at the end of the rotor blades, the fluidic losses, and flow noise, the rotor blade is split in at least two partial blades at a set distance from the axis of rotation and forms a loop. One partial blade extends in the direction of rotation in relation to the rotor blade. The other partial blade extends in a direction opposite the direction of rotation to the rotor blade. The two partial blades are interconnected in one piece at their ends, to encompass a loop surface extending essentially crosswise to the main direction of flow, through which the fluid flows.

Description

The invention relates to a rotor, which in operation in a main flow direction of a fluid flows through, with a rotor blade arranged rotatably about a rotor axis, which extends at least in sections away from the rotor axis into the fluid and at a predetermined distance from the rotor axis in at least two Partial sheets is split, one partial sheet in the direction of rotation and the other Part of the blade is curved away from the rotor blade against the direction of rotation and the the two partial sheets are joined together to form a loop.

Rotors for generating propulsion or for generating a torque are in the Known in the prior art and in the first case include propellers and propellers, Blowers, fans, fans etc., in the second case flow-driven repellers, Turbines and wind turbines. With ship propeller or airplane propeller turns Rotor blade that is attached to a hub around the axis of rotation and generated due to it Profile shape or due to its employment when rotating about the axis of rotation a driving force. The driving force is averaged over one revolution of the rotor blade mostly essentially parallel to the axis of rotation and propels the ship or aircraft forward. Helicopter rotors can be adjusted by rotating the rotor blades during rotation a propulsive force inclined with respect to the axis of rotation is generated about the axis of rotation. Here, the main flow direction is understood to mean that direction which the flow passes the rotor when you look at the rotor in a far-field view reduced to one level.

The efficiency of rotors is determined by flow losses in the form of vortex formation, Swirl and - when operating the rotor in liquid fluids - reduced by cavitation. Sound radiation is also often a problem. That of ship and aircraft propellers, Helicopter rotors, wind turbines, various fans and blowers, For example, noise caused in air conditioning systems has a significant share in of today's acoustic environmental pollution.

Generic rotors are known from the prior art, which compared to conventional rotors to improve efficiency and reduce the noise emission or sound generation.

A rotor is known from DE 42 26 637 A1, in which a rotor blade consists of two partial blades is split. This rotor can reduce vibrations during operation become.

Another rotor is known from DE-PS 83050. This rotor leads to an increase the reaction pressure.

In US 1,418,991 is a rotor with one at a distance from the axis of rotation in two Sub-blades split rotor blade described, the sub-blades relative to Extend the rotor blade in and against the direction of rotation of the rotor. Through the rotor of the US 1,418,991 the flow resistance can be reduced.

Generic rotors are known from US 3,504,990 and US 4,445,817 and DD-PS 614 381 known.

The rotor shown in US 3,504,990 has support arms which do not influence the flow. At the ends of the support arms an annular surface is attached, which over their Extent of the propulsion generated by the rotor.

A rotor is known from US Pat. No. 4,445,817 and DD-PS 614 381, in which rotor blades from a rotor base that extends flat and transverse to the main flow direction and are constructed from a strip-shaped rotor blade. Each strip-shaped rotor blade is bent and attached to the rotor blade following in the direction of rotation. Also at This rotor is propelled exclusively on the outer circumference of the rotor blade.

In DE 197 52 369 a transverse drive body is shown, its transverse to the direction of flow lying end is split to form a loop.

EP 0 266 802 shows a jacket propeller, the conveyor blades of which have cone jacket cutouts form. The jacket and conveyor sheet each enclose holes which flow the flow rate.

A disadvantage of the rotors known from the prior art is that they are achieved improvements in efficiency and noise emissions for today's applications are no longer sufficient.

The present invention is therefore based on the object by simple constructive Measures to improve the rotors mentioned above in such a way that you Efficiency is increased.

In particular, the aim is that the rotor in addition to an improved efficiency generates less noise and is therefore particularly environmentally friendly.

According to the invention, this object is achieved on the one hand for a rotor of the type mentioned at the beginning solved in that a driving force or a torque can be generated about the rotor axis and that the rotor axis through the loop surface enclosed by the loop passes through.

On the other hand, the above task for a rotor of the type mentioned above solved that in operation by the rotor blade a driving force or a torque can be generated about the rotor axis and that the leading edge of the one front Partial blade at least in an area near the rotor blade in the main flow direction is upstream of the leading edge of the other, rear partial sheet.

This solution is simple and leads to a significant reduction in noise from the rotors.

By merging the partial sheets into a loop takes place along the Loop contour a continuous change in circulation from one to the other Partial sheet instead. With a change of sign of the circulation between the two partial sheets the circulation along the loop contour must have a zero crossing. The loop therefore forms a device through which the circulation of the Rotors over the entire loop circumference and thus in the wake generated Vortex is evenly distributed. This is one compared to the state of the Technology more even circulation distribution along the rotor blade and along the the loop-forming partial sheets reached. The vortex strength is spatial across the entire Loop circumference distributed, resulting in lower losses through vortex formation and leads to less generation of flow noise.

The loop-shaped ring closure of the partial leaves also results in a high mechanical Stability of the rotor reached. This can reduce the structural weight and an overall more delicate construction can be achieved. Also in the sections the loop formed by the partial leaves, on which the circulation is only slight tread depth, which only makes a small contribution to propulsion can be reduced. In this way the frictional resistance can be reduced.

If the axis of rotation for a rotor with only one rotor blade runs through the loop plane, this simple design measure allows unbalance in the Avoid rotating the rotor.

The rotor blade and the partial blades can be used for simple applications such as simple fans or fans as well as toy airplanes and toy wind turbines for example through inclined surfaces, for technically more complex applications such as aircraft propellers or ship propellers, for example by hydrofoil-like ones Profiles with a certain thickness distribution and curvature can be formed. One along of the rotor blade and the partial blades depending on the local flow conditions Changing profile leads to particularly favorable flow properties and to an improved efficiency. In the same context, the Blade depth and the local angle of attack the local flow conditions be adjusted.

The generation of propulsion or torque is also essential to the invention through the rotor blades themselves. The principle according to the invention differs with this principle Rotor from the rotor of DD-PS 61 438. This rotor also forms one Loop, but the rotor shown there has no rotor blades that differ from extend away from the axis of rotation into the flow and generate a propulsion: the loop-shaped, circumferential band is rather held by support arms, which affect or disturb the liquid flow as little as possible allowed to. The propulsion is exclusive to the rotor of DD-PS 61 438 or US 4,445,817 generated by the circulating belt, which is a relative working movement similar to the wave motion of a fish's tail or a bird's wing. This type of jacking is poor in efficiency. With the above In principle, the rotor according to the invention also differs from other known ones Loop constructions, for example the leaf apparatus of US 5,890,875. Even there no rotor blades are provided, so that only low propulsive forces or torques be achieved.

In the embodiment according to the invention, the one partial sheet can be at least in one Area near the rotor blade both in the direction of rotation and in the main flow direction lie in front of the other sheet. Either the leading edge of one partial sheet in the main flow direction upstream of the leading edge of the other Partial sheet or one partial sheet also completely upstream of the other partial sheet lie. With this arrangement of the partial sheets, the flow of the Print side of the front, upstream partial sheet, at least in the area of the rotor blade is directed to the suction side of the rear, downstream rotor blade become. Due to the faster flow on the vacuum or suction side of the upstream sub-sheet becomes the flow around the downstream sub-sheet Kinetic energy is supplied, which leads to a more stable flow around the rear partial leaf leads.

In a preferred embodiment of the rotor, the partial blades can gradually move in bend away from the rotor blade essentially without any transition. Through the continuous Shape transition of the partial sheets can corner currents, which change with strong Operating conditions of the rotor otherwise occur at the kinks and too Losses can be avoided.

In a further very advantageous embodiment, the two partial sheets can be on their Ends be integrally connected. This structure is thanks to the mechanical Connection of the partial blades particularly stable and resilient, so that the rotor generated vibrations can be reduced. It also increases the risk of injury minimized by the tips of the partial sheets.

In an advantageous development of the invention, the two partial sheets can preferably merge smoothly. This means that the two partial sheets have essentially the same profile shapes at their connection point and their Contours are largely connected with each other. For example done by integrally molding the two connected sub-sheets.

The flow losses can be minimized independently of one another by that in a further advantageous embodiment, the trailing edge of the rotor blade preferably in the trailing edge of the rear, downstream partial sheet continues fluently. Likewise, in a further advantageous embodiment Leading edge of the rotor blade in the leading edge of the front, upstream Continue partial sheet. This prevents the flow due to irregularities is adversely affected at the leading edge. Likewise, the Circulation distribution even with small irregularities on the trailing edge on change the corresponding rotor or partial blade considerably. In a further embodiment, which is particularly advantageous in the case of a rotor according to the invention with only one rotor blade the axis of rotation can pass through the loop surface.

In a further embodiment, the rotor can have a plurality of in the direction of rotation preferably equally spaced rotor blades, in which the front, upstream partial blade of a rotor blade with the rear, downstream Partial blade of a rotor blade leading in the circumferential direction is connected. These designs represent a reversal of the circulation with a low cost of materials along the loop safely. Due to the higher number of rotor blades one can achieve overall greater propulsion with a smaller construction volume. The advantage of this Design lies in the combination of high propulsion or torque with one uniformly good distribution of the circulation in the wake of the rotor. Despite high In this configuration, the rotor remains quiet. Are preferred in this embodiment the partial blades each in the circumferential direction of adjacent rotor blades Forming a loop connected to each other.

To ensure optimal flow conditions on the rotor blade under various operating conditions and to reach the blades of the rotor, the blades and / or the partial sheets to changed local flow conditions, i.e. flow conditions, which are limited to the location of the respective rotor blade and / or partial blade, can be customized. For this purpose, the rotor blade and / or the partial blade can at least be provided in sections with an elastic outer skin. With suitable material coordination and / or appropriate pre-tensioning of the outer skin are local changes the profile geometry of the rotor blade and / or partial blade either solely on the basis the fluid mechanical forces acting on the profile, i.e. passive, or by means of a contour adjustment device, that is to say actively, without being raised, Wrinkles or kinks that negatively affect the flow occur on the outer skin. In addition, an elastic outer skin can be chosen with a suitable choice of elasticity a loss-free flow around the rotor blade and / or partial blade. A elastic outer skin is able to cope with pressure disturbances through locally narrowly limited deformation to respond and intercept these pressure disorders, resulting in a calmer and also leads to less noisy flow around the rotor blade and / or partial blade.

In a further advantageous embodiment, the rotor can also be equipped with a profile adjustment device be provided, which acts on the outer skin and through the outer skin for local or global change of a profile geometry of the rotor blade and / or the partial sheet is at least partially displaceable. It is under one local change a change in the profile geometry or the contour of the rotor or partial blade understood, which are only in a narrowly defined area of the rotor blade and / or partial sheet plays and the flow in other areas of the Leaves the rotor blade and / or partial blade essentially unaffected. A global one Changing the profile geometry, however, changes a large area of the profile geometry of rotor blade and / or partial blade and leads to a significant change in Flow characteristics of the rotor blade and / or partial blade.

In a further advantageous embodiment, the rotor can have a hub on which the rotor blade is held. The rotor blade can be adjusted via an angle of incidence be rotatably held on the hub to change its angle of attack. By changing the angle of attack of the rotor can be quite simple generated propulsion constant over large ranges of the rotational speed of the rotor maintained or adapted to the current operating conditions. With elastic Execution of the rotor is also a torsion which is favorable for the flow Leaf structures along the loop lines enabled. An angle of incidence adjustment device can also be used be provided by which the partial sheet for changing an angle of attack is rotatably held on the rotor blade. An angle of attack is to be understood in general, in flow technology, an inclination of the chord of the rotor blade and / or partial blade relative to the local flow against the rotor blade and / or Part sheet. The chord connects the leading edge, i. H. the connecting line of the front stagnation points of the rotor blade and / or partial blade, with the trailing edge, that is the connection of the rear stowage points of the rotor blade and / or partial blade.

In a further advantageous embodiment, an arrow angle adjustment device be provided, through which the rotor blade essentially in the direction of propulsion is pivotally held relative to the hub. With this adjustment device Arrow angle of the rotor blade, i.e. the angle of the leading edge relative to the direction of the Main flow can be changed and the generated in the wake of the rotor blade Distribute circulation better. A similar device can also be used between the rotor blade and partial sheet can be provided to also change the sweep of the partial sheet. To at the setting of the arrow angle also the rotating component of the flow against the rotor blade the arrow angle adjustment device can be advantageous the rotor blade or partial blade also around a flow running parallel to the axis of rotation pivot.

In a further advantageous embodiment, a can be arranged between the rotor blade and the partial blade Spreading angle adjustment device can be provided with which at least one partial sheet of the The rotor is connected in such a way that it points essentially in the direction of rotation Spread angle between two blades of a rotor blade depending on the operating state of the rotor can be adjusted.

Another adaptive adjustment option of the rotor geometry, which reduces the efficiency improved a variety of operating situations, can be advantageous in another Embodiment can be achieved by an extension device between the rotor blade and partial sheet is provided and through which the partial sheet relative to the direction of extension the rotor blade is held extendable. By extending the partial sheets and / or the Rotor blade, the area generating the propulsion is increased, so that the same Circulation per unit area of the rotor blade and / or the partial blade is higher Propulsion can be generated.

Finally, two or more rotors according to the invention can be connected in series. If the rotors rotate in opposite directions relative to each other, overlap in the wake of these two rotors, the respective vortex strengths and extinguish partially out. With suitable coordination, this can even result in a complete Extinction of the component of the vortex strength in the direction of the axis of rotation, the Swirls, at least one of the rotors can be achieved. This can be eliminated of the swirl in the wake of the series-connected propellers minimize the losses. An optimal superposition of the vortex strengths is achieved when the rotors in have approximately the same diameter. The upstream rotor can also act as a stator be designed, whereby the design effort is reduced.

The structure and function of a rotor according to the invention with a rotor blade split into partial blades explained using exemplary embodiments.

Fig. 1

ein erstes Ausführungsbeispiel eines erfindungsgemäßen Rotors mit zwei jeweils gespaltenen Rotorblättern;

Fig. 2A

einen Detailausschnitt II einer ersten Variante des Rotors der Fig. 1;

Fig. 2B

einen Detailausschnitt II einer zweiten Variante des Rotors der Fig. 1;

Fig. 3

einen Detailausschnitt II eines zweiten Ausführungsbeispiels des erfindungsgemäßen Rotors;

Fig. 4

ein drittes Ausführungsbeispiel eines erfindungsgemäßen Rotors;

Fig. 5

ein viertes Ausführungsbeispiel des erfindungsgemäßen Rotors;

Fig. 6

ein fünftes Ausführungsbeispiel des erfindungsgemäßen Rotors;

Fig. 7

zeigt ein weiteres Ausführungsbeispiel des erfindungsgemäßen Rotors;

Fig. 8A - 8C

zeigen Veränderungen der Profilgeometrie eines adaptiven Rotorblattes gemäß einem weiteren Ausführungsbeispiel der Erfindung;

Fig. 9

zeigt die Verstellmöglichkeiten bei einem adaptiv ausgebildeten, erfindungsgemäßen Rotorblattes gemäß einem weiteren Ausführungsbeispiel;

Fig. 10A und 10B

zeigen das Wirbelfeld im Nachlauf eines herkömmlichen und eines erfindungsgemäßen Propellers;

Fig. 11

zeigt ein weiteres Ausführungsbeispiel der Erfindung, bei dem zwei Rotoren hintereinander geschaltet sind;

Show it:

Fig. 1

a first embodiment of a rotor according to the invention with two split rotor blades;

Figure 2A

a detail section II of a first variant of the rotor of FIG. 1;

Figure 2B

a detail section II of a second variant of the rotor of FIG. 1;

Fig. 3

a detail section II of a second embodiment of the rotor according to the invention;

Fig. 4

a third embodiment of a rotor according to the invention;

Fig. 5

a fourth embodiment of the rotor according to the invention;

Fig. 6

a fifth embodiment of the rotor according to the invention;

Fig. 7

shows a further embodiment of the rotor according to the invention;

Figures 8A-8C

show changes in the profile geometry of an adaptive rotor blade according to a further embodiment of the invention;

Fig. 9

shows the adjustment options in an adaptively designed rotor blade according to the invention according to a further embodiment;

10A and 10B

show the vortex field in the wake of a conventional and a propeller according to the invention;

Fig. 11

shows a further embodiment of the invention, in which two rotors are connected in series;

First, the basic structure of a rotor according to the invention is based on the described in the embodiment shown in FIG. 1.

1 shows a rotor 1 in a plan view in the direction of an axis of rotation 2, around which the rotor is rotatably mounted. In the form shown, the rotor 1 for Fans, propellers, rotors, but also as a turbine or wind turbine. A hub 3 is arranged around the axis of rotation, to which two rotor blades 4 are fastened. These rotor blades 4 each extend substantially in the radial direction from the hub or axis of rotation into a fluid that surrounds the rotor 1.

Each rotor blade 4 is split into two partial blades 5, 6. The partial sheets 5,6 each in Direction of rotation of successive rotor blades 4 are connected to form a loop.

In operation, the rotor 1 rotates about the axis of rotation 2 in a direction of rotation D. The rotor 1 can passively rotate with a flow, as is the case with Wind turbines is the case. In this case, the rotor 1 is essentially along flow to axis 2. With appropriate profiling and / or adjustment of the rotor blades 4 and the partial sheets 5, 6, a torque is then generated about the axis of rotation 2, via a generator (not shown) that rotates with the rotor Rotor shaft (not shown) is connected to be used for power generation can. Conversely, the rotor 1 can also be driven by a drive motor (not shown) are actively driven, due to the rotation of the rotor due to the corresponding trained profiling and / or employment of the rotor blades 4 and / or Sub-blades 5, 6 a flow through the of the rotor blades 4 and the sub-blades 5, 6 swept area and generated by the loop and a propulsion.

2A and 2B is to explain the geometry of the rotor blade and the Partial sheets a detail section II of FIG. 1 is shown. The one formed by the rotor blades Loop is not shown in Figures 2A and 2B for simplicity.

The rotor blade 4 is at a distance A upstream in the main flow direction located - part 5 and a rear - located downstream in the main flow direction - Split sheet 6. The rotor blade 4 goes smoothly without cross-sectional jumps in the respective sub-sheet 5, 6 over.

The leading edge 7 of the rotor blade 4 located in the main flow direction settles continues seamlessly in the leading edge 7a of the front partial sheet 5. The trailing edge 8 of the The rotor blade 4 continues seamlessly in the trailing edge 8b of the rear partial blade 6. The front sub-blade 5 forms after splitting the rotor blade 4 into the two Sub-sheets 5, 6 have their own trailing edge 8a, which is at least close in area of the rotor blade 4, that is to say in the area around the splitting, in sections with a leading edge 7b, which is formed by the rear partial sheet 6, overlaps. However, it can this overlap also disappears.

The front sub-sheet 5 is curved in the direction of rotation D relative to the rear sub-sheet 6, so that the front sheet 5 spreads away from the rear sheet 6.

2A, looking in the main flow direction along the Axis of rotation 2, the surface 9 of the rotor blade 4 and the two sub-blades 5, 6 represents acted pressure side, in the case of a propeller, rotor and the like, the suction side. suction and pressure side differ by the pressure conditions prevailing on them from each other. The mean fluid pressure on the suction side is lower than that medium fluid pressure on the pressure side. Due to this pressure difference the direction the axis of rotation 2 directed propulsion of the propeller or in a wind turbine Torque generated. The suction side and pressure side are each through the leading edges 7, 7a and 7b and separated by the trailing edges 8, 8a and 8b.

The leading edge is the connecting line pointing in the direction of the flow against the blade the stagnation points of the rotor blade or the partial blades, i.e. those Points at which the average speed relative to the rotor structure in question is zero becomes. The trailing edge results accordingly from the connecting line of the rear Stagnation points.

In the exemplary embodiment in FIG. 2A, the front partial sheet 5 is configured larger than the rear sub-blade 6 and the rotor blade divided in the profile depth.

Alternatively, the rotor blade 4 cannot be in the direction of the profile depth, but in the thickness direction, for example along the center line, in a suction-side partial sheet 11 and in one partial sheet 10 to be split A rotor according to the invention with in the thickness direction split rotor blade is also shown in Fig. 3 as a detailed view II. The center line of a profile is the line from the center of the circle Circles touching the top and bottom of the profile inscribed in the profile.

Any transitional forms of the rotor blade according to the invention are also conceivable, where the partial sheets can overlap and the leading edge or the Trailing edge of a partial blade with the suction or pressure side of the rotor blade can merge.

Due to the curvature of the partial blade 5 in the direction of rotation of the rotor 1, the front Part 5 on the suction side of fast flowing fluid towards the rear Part 6 steered. This leads to an accelerated and therefore more stable flow of the rear sub-sheet.

The suction-side partial sheet 11 forms its own pressure side (not designated). Likewise, the partial sheet 10 on the pressure side forms its own suction side 9a. The suction side Sub-sheet 11 extends relative to the main rotor 4 in the direction of rotation D, the partial sheet 10 on the pressure side extends opposite the rotor blade 4 against the direction of rotation. The suction side of the partial blade 11 merges into the suction side of the rotor blade 4, the pressure side of the partial blade 10 in the pressure side of the rotor blade. In the embodiment 1, the two partial sheets 10, 11 are of approximately the same size. Indeed is also different here, similar to the variant of FIG. 2A large design of the partial sheets 10, 11 possible. The leading edges of the two partial sheets 10, 11 flow together to the leading edge of the rotor blade 4, the trailing edges of the two partial blades 10, 11 merge smoothly to the trailing edge of the rotor blade 4th

FIG. 2B shows a further variant of the rotor blade of FIG. 1 in a detailed view II.

2A and 2B differ in the respective curvature of the rotor blade in or against the direction of rotation, at a distance A, at which the rotor blade 4 is split, in the relative size of the partial sheets 5, 6 to each other and in the relative Size of the partial blades 5, 6 to the rotor blade 4.

In Fig. 2B a spread angle W is drawn, which characterize the angular amount to which the two partial sheets 5, 6, gap.

The spreading angle W can be in the space between the trailing edge of one (front) Sub-sheet and the leading edge of the other (rear) sub-sheet or between the Center lines M of the two partial sheets are measured. The center line connects them Points that cut the tendons in half in a radial cut.

In the rotor of FIG. 2B, the rear partial blade 6 is larger than the front one Sub-sheet 5. This increases propulsion from the rear sub-sheet 6 in a propeller or generates a greater torque with a repeller than from the front sheet 5, which leads to a correspondingly higher concentration of vortex strength in the wake of the rear sub-sheet 6 leads. By extending the tip of the leaf into a loop in this case, too, a favorable vortex distribution can be achieved in the wake, by, for example, the partial sheet with the greater profile depth a larger proportion on the loop space catch than the partial sheet with the smaller profile depth.

4 and 5 show further embodiments of an inventive, as a "Loop propeller" designed rotor with only one rotor blade 4. The rotor of the 4, the front partial sheet 5 is connected to the rear partial sheet 6 in a loop, so that a loop surface 12 is formed. This loop surface rotates in the direction of rotation D and the fluid flows through it. The two partial sheets 5, 6 are curved that the axis of rotation 2 lies within the loop surface 12. The merger of the Sub-blades 5, 6 are therefore typically on the opposite side with respect to the rotor blade 4 Side of the axis of rotation. 4 is the front partial sheet 5, however, is relatively long and curved in a spiral, whereas the rear partial sheet 6 is shorter and extends substantially radially away from the axis of rotation 2. The front one Sub-sheet 5 and the rear sub-sheet 6 are connected to one another in an area B, which in this particular configuration roughly extends the main page lies. In this area B, the circulation also changes its sign.

The partial sheets 5 and 6 merge seamlessly into one another, so that the smallest possible Disturbances in the flow around the loop propeller are generated. In the embodiment 4, the main rotor is strongly curved and splits in the direction of rotation D. at a relatively small distance A from the axis of rotation into the two partial sheets 5, 6 on.

In the embodiment of FIG. 4, the partial sheets 5, 6 have different lengths but about the same profile depth. However, partial sheets of the same size can also be found here used or the profile depth of the partial sheets can vary.

The direction of rotation of the circulation must change along the transition from partial sheet 5 to partial sheet 6, along the edge of the loop. If you set a positive sign for a direction of rotation of the circulation and designate the amount of circulation in the area of the splitting of the rotor blade 4 into the two partial blades 5, 6 or 10, 11 with Γ ₀ , then the circulation along the loop must be the same for partial blades of + Γ _0/2 to change -Γ _0/2.

This change in circulation takes place gradually along the loop element. Because the strength of the vortices induced in the wake from the local change in strength depends on the bound vertebra, this results in a continuous overall Fluidized bed in the wake that envelops the propeller jet and roughly that everywhere has the same strength.

4, the entire outer contour can be used to The most favorable tunneling distribution for each application (with a driven one Rotor) or energy yield (in the case of a passively operated rotor) along the rotor blades and get sub-sheets. For example, by pulling more outwards Loop elements or a somewhat more ring-shaped design the load the outer parts can be varied. This in turn can be used, for example, at Propellers reduce the risk of cavitation. Through the loop-shaped The loop propeller achieves a high mechanical ring closure of the partial blades 5, 6 Stability, which makes it easier to build the loop propeller. Also in sections of the loop propeller on which the circulation is only small, in particular in the area of the change of sign of the circulation, the profile depth is reduced become.

5 and 6 show further exemplary embodiments of the loop propeller.

The single-bladed loop propeller of FIG. 5 has compared to the embodiment 4 shows a less strongly curved rotor blade 4. The distance A at which the rotor blade 4 divides, is larger and the partial blades are approximately the same length. Overall is the loop surface 12 in the loop propeller of FIG. 5 is rounder, which is what Balancing the rotor easier.

The exemplary embodiments in FIG. 6 show a further exemplary embodiment of a two-leaf Loop propeller. In contrast to the loop propeller of FIG. 1, the Loop propeller of FIG. 6 provided with elongated loop surfaces 12, which are essentially through a larger section A between the splitting of the rotor blade 4 is reached in the two partial sheets 6. FIG. 6 also shows area B, in which the front partial blade 5 of the one rotor blade 4 with the rear partial blade 6 of the other rotor blade 4 is connected. In this area B the circulation changes their sign and has an amount close to zero. This area B is with a shallow profile depth. In addition, the profile can be very slim in this area and be kept symmetrical, since area B is for propulsion or energy generation of the loop propeller 1 contributes very little. So that in this Area both the form resistance and the friction can be minimized.

The principle of the loop propeller according to FIGS. 1 to 6 can also apply to multi-leaf Rotors are transmitted. An embodiment of a multi-blade loop rotor is shown in FIG. There is a rotor 1 consisting of three rotor blades 4, which in Direction of rotation D are evenly spaced from each other. The rotors 4 are at the same distance A from the axis of rotation 2 in a front sheet 5 and divided a rear sheet 6. The front partial blade 5 of a rotor blade 4 is with the Sub-blade 6 of the next rotor blade 4 connected in the direction of rotation. Depending on the application can change the direction in which the partial sheets are relative to each other connected, can also be reversed.

This creates three loops with loop surfaces 12. The loop surfaces 12 point each have a common leading edge 7, which is continuous from the front edge a rotor blade, from the front partial blade 5 of the same rotor blade 4 and from the rear Sub-blade 6 of the other rotor blade 4 is formed. The trailing edge is also 8 that of sheets 5 and 6 and the rotor blade that connects to sheet 6, formed loop formed consistently.

Based on the principle according to the exemplary embodiment in FIG Realize loop rotors with any number of rotor blades 4. there more complicated geometries are also possible in which the loops are nested be, for example, by the front partial blade 5 of a rotor blade not with the rear partial blade 6 of an adjacent rotor blade 4, but with one rear partial blade of a rotor blade 4 further away is connected.

As a further development of this variation option, splits into more than two partial blades possible, which in the manner according to the invention lead to more spatial rotor structures can be linked.

According to the invention it is further provided that the rotor 1 is provided with devices which is an adaptation of the rotor blade and partial blade geometry to different flow conditions allows.

Such an adaptation can be achieved in that the rotor blade 4 and / or at least one of the partial sheets 5 and 6 consist of an elastic material or have an elastic outer skin. The main advantage is that gradual changes in the flow geometry of the rotor blade and the Partial sheets are possible in particular along the loop structure.

With an elastic outer skin, for example, the geometry of a profile of the Rotor blade 4 and / or a partial blade 5 can be changed. This is in Fig. 8A to 8C shown schematically.

8A shows a section along the line IIX - IIX of FIG. 1. The section line IIX - IIX runs perpendicular to a radius beam coming from the axis of rotation 2. The Profile 13 is covered with an elastic and flexible outer skin 14. The profile 13 of the The rotor blade 4 or one of the partial blades 5, 6 is provided with a flexible outer skin 14. The flexible outer skin 14 can be the profile 13 completely, or only in sections surrounded at the points where the contour of the profile 13 changes in a targeted manner shall be.

In the interior of the profile 13, a contour adjustment device is provided, which is shown in FIG. 8A by way of example on the basis of an eccentrically mounted nose 15 of the profile Cam 16 and by means of connecting elements 17, the suction side 9 of the profile 13 connect to the pressure side 18. The contour adjustment device can be dependent change the shape of the profile from the inflow of the profile 13. For example can, as shown in FIGS. 8B and 8C, by the eccentrically mounted cam 16th when they are rotated about the axis of rotation 19, the angle of inclination of the nose is changed. Thus, the angle of attack N between the through the Arrow marked flow of the profile 13 and the leading edge with the Tendon S connecting trailing edge enlarged. To on the suction side 9 in the strong Angle of attack N of FIG. 8C was to avoid detachment at the front edge the curvature of the profile 13 in FIG. 8C is increased by the contour adjustment device, and lowered the nose in the direction of the inflow.

This can be done, for example, by rotating the cam 16 and by moving the connecting elements 17 can be achieved relative to each other. By shifting the Connecting elements 17 results in a segmental deformation of the profile that the elastic outer skin can easily follow without affecting the smoothness of the contour becomes. A change in the rear profile area can also be carried out in a similar way bring about, for example generate an S-beat. In the interaction of several Contour adjustment devices can thus the profile geometry in a very complex manner to be influenced. Other principles of the contour adjustment device are also conceivable such as several eccentric cams distributed over the profile, the parts of the outer skin bulge outwards or inwards when rotating Profiles inflated or deployed by rotational forces 13.

Also flexible profiles that are created under the influence of the flow Deforming forces at least in sections are conceivable. With such profiles the flow is passive, i.e. without external energy supply, solely due to the influenced by the flow itself applied energy.

In the continuation of these principles, exemplary embodiments are finally conceivable, that combine active and passive profile changes in an advantageous way.

Further adjustment options for a rotor are shown in FIG. 9. Through an articulated Connection of a rotor blade 4 to the hub 3 can be via a not shown Arrow angle adjustment device the inclination of the leading edge of the rotor blade 4 relative to the plane of rotation of the rotor 1 along the arrow PR, that is, in the direction of propulsion or set in the main flow direction. The vertebral strength concentration is reduced by the arrow angle in the wake through the secondary flow along the leading edge also influence in the radial direction. A similar effect can also be seen achieve with the sub-pages 5 and 6, if these also via a hinge connection with its own arrow angle adjustment device along the arrows PT in the direction of Propulsion and / or adjustable in the main flow direction. An angle of incidence adjustment device can also be used (not shown) can be provided in which the rotor blade 4 um an axis of rotation running essentially radially to the axis of rotation 2 along the arrows AR is pivotable. By changing the angle of attack at different Speeds and flow velocities of the rotor blade 4, the propulsion or optimize the torque for a passively operated rotor. Part 5, 6 can be arranged on the rotor blade 4 in this way via an angle of incidence adjustment device be that the angle of attack of the partial blades in the direction of arrows AT relative to the rotor blade 4 can be changed.

The operation of the rotor 1 according to the invention is schematic in FIGS. 10A and 10B shown. A conventional two-bladed propeller 20 is shown in FIG. 10A. A tip vortex is formed at the tips of each rotor blade of the rotor 20, which in the wake of two vortex loops 21, 22 twisted together in a helix leads. The vortex strength in such a conventional rotor is in these vortex threads 21, 22 concentrated. This strong vortex concentration is with high losses and associated with increased noise. Such a vortex thread 21, 22 hits on a body, it is known that this leads to the generation of flow noise.

In contrast, in the loop rotor 1 according to the invention shown in FIG. 10B, the Circulation in the wake of the loop propeller 1 or the rotor 1 with the invention divided rotor blade 4 evenly distributed. This leads to less Losses and less flow noise. The uniform, envelope-shaped Distribution of the vortex strength can be similar in the wake of the rotor according to the invention act like a casing of a casing propeller. Through the even distribution the vortex strength in the wake of the rotor is possible by superimposing two wakes with corresponding vortex strengths in the respective wake the component to cancel out the vortex strength in the direction of the axis of rotation. A practical realization this principle is discussed in the following embodiment.

11 shows an arrangement of loop propellers 1 or of rotors 1 with the invention divided rotor blade 4 through which the fluid mechanical losses can be reduced again. In the main flow direction H are two according to the invention Rotors 1a and 1b arranged one behind the other. The speeds of rotation of the two rotors 1a and 1b are of different sizes. With appropriate coordination of the relative rotational speeds of the rotors 1a and 1b, the swirl can be removed from the wake 30 of the front rotor 1a, so that the Caster of rotor 1 b is no longer twisted. The flow swirl leads to the above-mentioned helical twisting of the vertebrae in the wake of the Rotor, as indicated schematically in FIG. 11. The twist therefore creates additional Energy stuck in the rotation of the flow field in the wake, leading to the actual one Energy generation or generation of propulsion of the actively or passively operated Rotors cannot be used. By turning the rear counter-clockwise This swirl is removed from rotor 1b, converted into propulsion and in the wake of the rotor 1b, the screw-like twisting of the swirl field no longer takes place.

The rotors 1a and 1b have to reduce the flow noise and vibrations due to interference not the same number of sheets or sheet geometries. By corresponding configuration, the front rotor 1a can, for example, have more swirl than Generate propulsion and the rear rotor 1b more propulsion than swirl. In extreme cases the front rotor 1 can be designed as a stator.

It is also conceivable to arrange a plurality of rotors to form a free jet turbine.

Claims (13)

1. Rotor (1), which in operation is flown through by a fluid in a main flow direction (H), said rotor having a rotor blade (4) arranged rotatable around a rotor axis (2) and extending at least partially away from said rotor axis (2) into said fluid, said rotor blade being split into at least two partial blades (5, 6) at a predetermined distance (A) from said rotor axis, one partial blade (5, 6) being curved in a direction of rotation (D) away from the rotor blade (4) and said other partial blade being curved against said direction of rotation (D) away from said rotor blade (4), said two partial blades (5, 6) being connected to form a loop, characterized in that a propulsion force or an angular momentum around said rotor axis (2) is generated in operation by said rotor blade (4), and in that said rotor axis (2) passes through the loop area (12) enclosed by said loop.
2. Rotor (1) according to Claim 1, characterized in that the leading edge (7a) of the one, front, partial blade (5, 6) is situated in the main flow direction (H) upstream of the leading edge (7b) of the other, rear, partial blade (6) at least in an area close to said rotor blade (4).
3. Rotor (1), which in operation is flown through by a fluid in a main flow direction (H), said rotor having at least two rotor blades (4) arranged rotatable around a rotor axis (2) and extending at least partially away from said rotor axis (2) into said fluid, said rotor blade being split in at least two partial blades (5, 6) in a predetermined distance (A) from said rotor axis, one partial blade (5, 6) being curved in a direction of rotation (D) away from the rotor blade (4) and the other partial blade being curved against said direction of rotation (D) away from said rotor blade (4), one partial blade (5, 6) of one rotor blade (4) being respectively connected with a partial blade (5, 6) of the other rotor blade (4) to form a loop, characterized in that a propulsion force or an angular momentum around said rotor axis (2) is generated in operation by said rotor blade (4), and in that the leading edge (7a) of said one, front, partial blade (5, 6) is situated in the main flow direction (H) upstream of the leading edge (7b) of said other, rear, partial blade (6) at least in an area close to said rotor blade (4).
4. Rotor (1) according to any one of the above claims, characterized in that the trailing edge (8) of said rotor blade (4) continues as the trailing edge (8a) of the rear partial blade (6).
5. Rotor (1) according to any one of the above claims, characterized in that the leading edge (7) of said rotor blade (4) continues as the leading edge (7a) of the front partial blade (5).
6. Rotor (1) according to any one of the above claims, characterized in that said two partial blades (5, 6) that are connected to form a loop merge smoothly with each other.
7. Rotor (1) according to any one of the above claims, characterized in that the front partial blade (5) is connected with the rear partial blade (6), respectively.
8. Rotor according to any one of the above claims, characterized in that at least one of said rotor blade (4) and said partial blade (5, 6; 10, 11) is at least partially provided with an elastic outer skin (14).
9. Rotor according to any one of the above claims, characterized in that a profile adjustment means is provided, by which the contour (13) of at least one of said rotor blade (4) and said partial blade (5, 6; 10, 11) is at least partially adjustable.
10. Rotor according to any one of the above claims, characterized in that an angle-of-attack adjustment means is provided, said angle-of attack adjustment means supporting at least one of said rotor blade (4) and said partial blade (5, 6) rotatable at said rotor blade (4) for adjustment of the angle of attack.
11. Rotor according to any one of the above claims, characterized in that a sweep angle adjustment means is provided, said sweep angle adjustment means supporting at least one of said rotor blade (4) and said partial blade (5, 6) on said rotor blade (4) pivotable essentially in the direction of propulsion.
12. Rotor according to any one of the above claims, characterized in that a spread angle adjustment means is provided between said rotor blade (4) and said partial blade (5, 6; 10, 11), through which said spread angle adjustment means at least one partial blade (5, 6; 10, 11) is pivotally supported at the rotor blade (4) such that a spread angle substantially pointing in the direction of rotation (D) is variable between two partial blades (5, 6; 10, 11) of a rotor blade (4).
13. Rotor according to any one of the above claims, characterized in that an extension means is provided between said rotor blade (4) and said partial blade (5, 6; 10, 11), said extension means supporting said partial blade (5, 6; 10, 11) with respect to the direction of extension of said rotor blade (4) extendably into the fluid.

Images